To stop bad breath from your stomach you can eat some fresh parsley or even mint leaves.
The chewing on and eating of the fresh parsley or mint leaves can help clean your mouth and make your stomach smell better as well.
Even though you cannot smell your stomach it can smell pretty bad depending on what you've eaten and by making your stomach smell better you won't have as bad of breath.
The mint and parsley also make your breath smell better.
Make sure to brush your teeth often, use mouthwash, floss your teeth etc.
Keeping your teeth and mouth clean get rid of bacteria which can cause bad breath.
It also prevents tooth decay, gum disease and cavities as well as tooth infections.
Chewing on some mints can also help make your breath smell better when it's smelling bad.